U.S. patent number 10,768,578 [Application Number 15/770,340] was granted by the patent office on 2020-09-08 for solar hand for a portable object such as a watch or a measuring instrument.
This patent grant is currently assigned to The Swatch Group Research and Development Ltd. The grantee listed for this patent is The Swatch Group Research and Development Ltd. Invention is credited to Pierpasquale Tortora.
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United States Patent |
10,768,578 |
Tortora |
September 8, 2020 |
Solar hand for a portable object such as a watch or a measuring
instrument
Abstract
A display hand for a portable object including an indication by
the display hand, inside which is housed a rechargeable electrical
energy source. The display hand includes at least one solar cell,
the electrical energy source being connected to the display hand to
be recharged.
Inventors: |
Tortora; Pierpasquale
(Neuchatel, CH) |
Applicant: |
Name |
City |
State |
Country |
Type |
The Swatch Group Research and Development Ltd |
Marin |
N/A |
CH |
|
|
Assignee: |
The Swatch Group Research and
Development Ltd (Marin, CH)
|
Family
ID: |
1000005042530 |
Appl.
No.: |
15/770,340 |
Filed: |
September 9, 2016 |
PCT
Filed: |
September 09, 2016 |
PCT No.: |
PCT/EP2016/071365 |
371(c)(1),(2),(4) Date: |
April 23, 2018 |
PCT
Pub. No.: |
WO2017/097449 |
PCT
Pub. Date: |
June 15, 2017 |
Prior Publication Data
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|
|
|
Document
Identifier |
Publication Date |
|
US 20180314210 A1 |
Nov 1, 2018 |
|
Foreign Application Priority Data
|
|
|
|
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Dec 11, 2015 [EP] |
|
|
15199649 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G04C
10/02 (20130101); G04B 19/305 (20130101); G04C
3/008 (20130101); G01D 13/265 (20130101) |
Current International
Class: |
G04C
10/02 (20060101); G01D 13/26 (20060101); G04C
3/00 (20060101); G04B 19/30 (20060101) |
Field of
Search: |
;368/205,226 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
0 872 783 |
|
Oct 1998 |
|
EP |
|
2 950 168 |
|
Dec 2015 |
|
EP |
|
2 664 994 |
|
Jan 1992 |
|
FR |
|
3 007 200 |
|
Dec 2014 |
|
FR |
|
Other References
International Search Report dated Dec. 5, 2016 in PCT/EP2016/071365
filed Sep. 9, 2016. cited by applicant.
|
Primary Examiner: Leon; Edwin A.
Attorney, Agent or Firm: Oblon, McClelland, Maier &
Neustadt, L.L.P.
Claims
The invention claimed is:
1. A portable object inside which is housed a rechargeable
electrical energy source, comprising: a first display hand and a
second display hand, wherein the first display hand and the second
display hand are formed of at least one solar cell, the electrical
energy source being connected to the first and second display hands
for recharging, wherein the first and second display hands are
superposed and each includes a hole for passage of a drive arbor,
the drive arbor of the second display hand being arranged
concentrically inside the drive arbor of the first display hand,
with an insulating layer between the two drive arbors, and each of
the first and second display hands including a first pole and a
second pole, the first pole of the first display hand being
electrically connected to a first terminal of the energy source via
the drive arbor of the first display hand, the second pole of the
first display hand being connected to the first pole of the second
display hand via a contact piece that ensures electrical continuity
between the first and second display hands, and the second pole of
the second display hand being connected to the second terminal of
the energy source via the chive arbor of the second display
hand.
2. The portable object according to claim 1, wherein the solar cell
is a heterojunction cell.
3. The portable object according to claim 1, wherein the contact
piece is centered on the drive arbor.
4. The portable object according to claim 1, wherein each of the
first and second display hands includes a first, respectively a
second, annular element each including a hole at their center for
passage of the drive arbor of the first, respectively of the
second, display hand, the first and second annular elements each
including an upper surface portion directed towards an observer,
and with a lower surface portion opposite to the upper surface
portion, the first and second annular elements being formed of an
electrically conductive material.
5. The portable object according to claim 4, wherein the first and
second annular elements each carry the first and the second display
hand.
6. A timepiece comprising the portable object according to claim 1.
Description
FIELD OF THE INVENTION
The present invention relates to a solar display hand for a
portable object. The present invention concerns, in particular, a
set of solar display hands for a timepiece such as a wristwatch or
a measuring apparatus with an analogue display.
BACKGROUND OF THE INVENTION
In a known manner, timepieces are equipped with a dial formed of a
solar cell comprising a substrate, at least one plurality of
superposed layers defining at least one n-i-p or p-i-n element and
a conductive layer forming a first electrode intended to be exposed
to light radiation in order to power a horometrical circuit or an
electrical circuit of a timepiece, such as a watch.
Patent No EP 0872783 discloses a dial formed of a solar cell for a
timepiece. Such a dial is of questionable aesthetic appearance and
its electrical performance is average. Indeed, a dial formed of a
solar cell must be translucent, so that the cell is less visible
and cannot receive any type of finish or specific colours.
SUMMARY OF THE INVENTION
It is an object of the invention to overcome the various drawbacks
of these known techniques.
More specifically, it is an object of the invention to provide a
display hand formed of a solar cell to obviate the need for solar
dials.
These objects, in addition to others which will appear more clearly
below, are achieved by the invention by means of a portable object,
inside which is housed a rechargeable electrical energy source,
including at least a first display hand and a second display
hand.
According to the invention, said first display hand and said second
display hand are formed of at least one solar cell, the electrical
energy source being connected to the display hands for
recharging.
According to a preferential embodiment of the invention, the solar
cell is a heterojunction cell.
According to an advantageous feature of the invention, the first
and second display hands are superposed and each provided with a
hole for the passage of a drive arbor, the drive arbor of the
second display hand being arranged concentrically inside the drive
arbor of the first display hand, with the insertion of an
insulating layer between the two drive arbors, each of the the
first and second display hands respectively including a first pole
and a second pole, the first pole of the first display hand being
electrically connected to a first terminal of the energy source via
the drive arbor of the first display hand, the second pole of the
first display hand being connected to the first pole of the second
display hand via a contact piece which ensures electrical
continuity between the first and second display hands, and the
second pole of the second display hand being connected to the
second terminal of the energy source via the drive arbor of the
second display hand.
According to another preferred feature, the contact piece is
centred on the drive arbor.
Advantageously, each of the first and second display hands includes
a first, respectively a second, annular element, each having a hole
at the centre for the passage of the drive arbor of the first,
respectively the second, display hand, the first and second annular
elements each being provided with an upper surface portion directed
towards an observer, and with a lower surface portion opposite the
upper surface portion, the first and second annular elements being
formed of an electrically conductive material, the first and second
annular elements each carrying the first and second display
hands.
The invention also concerns a timepiece including at least one hand
according to the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
Other characteristics and advantages of the invention will appear
more clearly upon reading the following description of a specific
embodiment of the invention, given simply by way of illustrative
and non-limiting example, and the annexed Figures, among which:
FIGS. 1 and 2 are top and bottom views of a set of hands including
a solar cell according to the invention.
FIGS. 3 and 4 are exploded views of a set of hands including a
solar cell according to the invention.
FIG. 5 is a cross-sectional view of a set of hands including a
solar cell according to the invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
A control member according to a particular embodiment will now be
described below referring jointly to FIGS. 1 and 2.
The invention concerns a display hand 1 for a portable device
providing an indication by means of display hand 1, and inside
which is housed an electrical energy source 36.
According to the invention, display hand 1 is formed of at least
one solar cell, and electrical energy source 36 is connected to
display hand 1 for recharging.
Although those skilled in the art may think that a set of solar
hands 1, 2 cannot be a sufficient energy source compared to a dial,
the inventor proved that a set of solar hands could provide a
comparable energy source.
Assuming that there is luminance L at the surface of the watch, the
power produced by the solar dial watch is given by the following
equation:
P.sub.C=L.times.S.sub.C.times.T.sub.C.times.E.sub.C.times.T.sub.G
(1)
where S.sub.C is the surface of the dial, T.sub.C the transmission,
E.sub.C the efficiency of the solar cell and T.sub.G Ia
transmission of the crystal.
Typically, the following values are observed for equation (1):
S.sub.C=8.times.10.sup.-4 m.sup.2; T.sub.C=0.35; E.sub.C=0.04
By integrating these values in equation (1), one obtains:
P.sub.C=L.times.T.sub.G.times.1.12.times.10.sup.-5 W (2) For a
portable device, such as a watch, with solar hands, the power
produced is given by the following equation:
P.sub.A=L.times.S.sub.A.times.E.sub.A.times.T.sub.G (3)
where S.sub.A is the surface of two hands, and E.sub.A the
efficiency of the solar cell of the hands.
For a set of hour/minute hands, the surface
S.sub.A=4.4.times.10.sup.-5 m.sup.2.
According to a preferred embodiment of the invention, the solar
cell forming display hand 1 is a heterojunction cell.
Heterojunction solar cells are obtained by placing in contact
materials with different energy gaps. For example, the silicon
heterojunction consists of placing in contact hydrogenated
amorphous silicon (a-Si:H) with crystalline silicon (c-Si), since
the energy gap of a-Si:H is much higher than that of c-Si. Since
the conductivity of a-Si:H is much lower than that of c-Si, a
conductive layer must be added across its entire surface in order
to collect the current. On the illuminated side of the cell, this
conductive layer is generally formed of a transparent conductive
oxide (TOO), which collects the current. This TCO also ensures
satisfactory contact with the metal electrodes, while acting as an
anti-reflective layer.
The efficiency of currently available heterojunction cells is
E.sub.A=0.22. The thickness of such a cell is 150 .mu.m, which is
comparable to the thickness of the hands conventionally used in
portable objects such as watches.
By integrating the preceding values in equation (3), one obtains:
P.sub.A=L.times.T.sub.G.times.0.97.times.10.sup.-5 W (4)
Since the luminance and transmission of the crystal are the same in
both cases, the power obtained in equations (2) and (4) is quite
comparable in both cases.
Thus, the solution of solar hands has the advantage of overcoming
restrictions as regards decorations for a watch dial, for example,
since the dial can be made with the desired material, colour and
finish.
The solar hands can be made by means of a known method described in
Patent EP 0948060 in the name of Asulab S A. This Patent describes
the manufacture of a circular photovoltaic cell forming a dial for
a timepiece such as a watch. However, in this Patent, the invention
is not limited to dials, and can be used for the manufacture of
photovoltaic cells in any other form, particularly the manufacture
of solar hands.
In order to transport the energy collected by the solar hands, a
particular structure must be provided so that one of the poles of
one of the solar hands is connected to one of the poles of the
other solar hand, through the electrical contact between the two
hands, which allows the drive arbors of the two hands to be used
for the electrical connection of the solar hands to the terminals
of the energy source. Such a structure is described by the
Applicant in Patent Application No. EP14170094.8. In the following
description, the structure of that Patent Application has been
adapted to suit the use of solar hands.
In the example represented in FIGS. 1 and 2, the set of hands
according to the invention includes a first and a second display
hand, respectively 1 and 2. The first display hand 1 is formed of a
first annular element 4 extended by a portion 6 which can be formed
by at least one solar cell and which extends in a substantially
rectilinear manner. The first annular element 4 has a hole 8 at its
centre for the passage of a drive arbor 10 of first display hand 1.
First annular element 4 is provided with an upper surface portion
12 directed towards an observer, and with a lower surface portion
14 opposite to upper surface portion 12. The upper 12 and lower 14
surface portions of first annular element 4 are connected to each
other over the entire length of their perimeter by a lateral
surface 16. According to a feature of the invention which will be
described in more detail below, first annular element 4 is coated
with a layer of an electrically conductive material over its upper
12 and lower 14 surface portions, and inside hole 8 in which drive
arbor 10 is engaged.
In a similar manner to first display hand 1, second display hand 2
is formed of a second annular element 18 extended by a portion 20
which can be formed by at least one solar cell and which extends in
a substantially rectilinear manner. Second annular element 18 of
second display hand 2 has a hole 22 at its centre for the passage
of a drive arbor 24 arranged concentrically inside drive arbor 10
of first display hand 1. Second annular element 18 is provided with
an upper surface portion 26 directed towards an observer, and with
a lower surface portion 28 opposite to upper surface portion 26.
The upper 26 and lower 28 surface portions of second annular
element 18 are connected to each other over the entire length of
their perimeter by a lateral surface 30. According to a feature of
the invention which will be described in more detail below, second
annular element 18 is also coated with a layer of an electrically
conductive material over its upper 26 and lower 28 surface
portions, and inside hole 22 in which drive arbor 24 is
engaged.
First and second hands 1 and 2 include first and second poles,
respectively 32A, 32B and 34A, 34B, for the electrical connection
thereof to an electrical energy source 36 housed inside a frame,
for example of a wristwatch fitted with the set of display hands 1,
2. The electrical energy source 36 is, for example, a rechargeable
battery.
The first pole 32A of the first light source 32 is connected to
energy supply source 36 via drive arbor 10 of first hand 1, and the
second pole 32B of first light source 32 is connected to the first
pole 34A of second light source 34 in a manner that will be
described in detail below. Second pole 34B of second light source
34 is connected to energy supply source 36 via drive arbor 24 of
the second display hand 2. To this end, the drive arbors 10 and 24
of the first and second display hands 1 and 2 must be electrically
conductive and must be electrically insulated from each other by
the insertion of an insulating layer 38.
As mentioned above, the first and second annular elements 4 and 18
are coated over their upper and lower surface portions with a layer
of electrically conductive material. More specifically, drive arbor
24 is driven into a metallized hole 22 arranged in second annular
element 18. Consequently, upper surface portion 26 of second
annular element 18 is brought to the same electrical potential as
drive arbor 24. Conversely (see FIG. 4), a continuous trench 40,
arranged in lower surface portion 28 of second annular element 18
and made electrically insulating by the local removal of
electrically conductive material, surrounds drive arbor 24, so that
lower surface portion 28 is electrically insulated from drive arbor
24. Likewise, a continuous trench 42, which is closed on itself and
which is made insulating in the same manner as continuous trench
40, is arranged in upper surface portion 26 of second annular
element 18 so as to create an island 44 electrically insulated from
the rest of upper surface portion 26. A metallized through hole 46
made in the thickness of second annular element 18 allows island
44, arranged in upper surface portion 26, and lower surface portion
28 to be electrically connected to each other.
Likewise, drive arbor 10 is driven into a metallized hole 8 in
first annular element 4. Consequently, the lower surface portion 14
of first annular element 4 is brought to the same electrical
potential as drive arbor 10. Conversely, a continuous trench 48,
arranged in upper surface portion 12 of first annular element 4 and
made electrically insulating by the local removal of electrically
conductive material, surrounds drive arbor 10, so that upper
surface portion 12 is electrically insulated from drive arbor 10.
Likewise, a continuous trench 50, which is closed on itself and
which is made insulating in the same manner as continuous trench
48, is arranged in lower surface portion 14 of first annular
element 4 so as to create an island 52 electrically insulated from
the rest of lower surface portion 14. A metallized through hole 54
made in the thickness of first annular element 4 allows island 52,
arranged in lower surface portion 14, and upper surface portion 12
to be electrically connected to each other.
Finally, lower surface portion 28 of second annular element 18 is
placed in contact with upper surface portion 12 of first annular
element 4 via an electrically conductive and mechanically elastic
contact piece 56 disposed between first and second display hands 1
and 2 and centred on drive arbor 10. Island 44 arranged in upper
surface portion 26 is thus electrically connected to upper surface
portion 12 of first annular element 4, this upper surface portion
12 being in turn electrically connected to island 52 arranged in
lower surface portion 14 of first annular element 4.
According to the invention, the first pole 32A is electrically
connected to a first terminal of energy supply source 36 via drive
arbor 10 of first display hand 1. To this end, first pole 32A is
connected, for example by a wire bonding technique, to lower
surface portion 14 of first annular element 4. Second pole 32B is
connected to first pole 34A via contact piece 56, which ensures
electrical continuity between the first and second display hands 1
and 2. For this purpose, second pole 32B is connected to island 52
arranged in lower surface portion 14 of first annular element 4. By
means of metallized through hole 54, made in the thickness of first
annular element 4, island 52 is electrically connected to upper
surface portion 12 of first annular element 4, this upper surface
portion 12 being in turn connected, by means of contact piece 56,
to lower surface portion 28 of second annular element 18. Lower
surface portion 28 of second annular element 18 is in turn
connected to island 44 arranged in upper surface portion 26 of
second annular element 18 by means of metallized via 46. Finally,
first pole 34A is electrically connected to island 44 arranged in
upper surface portion 26 of second annular element 18. Second pole
34B is connected to the second terminal of energy source 36 via
drive arbor 24. For this purpose, second pole 34B is electrically
connected to upper surface portion 26 of second annular element
18.
Of course, the present invention is not limited to the illustrated
example and is capable of various variants and modifications that
will appear to those skilled in the art.
NOMENCLATURE
1. First display hand, 2. Second display hand, 4. Annular element
6. Substantially rectilinearly extending portion, 8. Hole, 10.
Drive arbor, 12. Upper surface portion, 14. Lower surface portion,
16. Lateral surface, 18. Annular element, 20. Substantially
rectilinearly extending portion, 22. Hole, 24. Drive arbor, 26.
Upper surface portion, 28. Lower surface portion, 30. Lateral
surface, 32A, 32B. First and second poles, 24A, 34B. First and
second poles, 36. Electrical energy source 36, 38. Insulating
layer, 56. Contact piece.
* * * * *